In a conventional supervisory control system, video cameras are placed at sites to be monitored, and video images are transmitted back to a control center in wired or wireless transmission way to provide remote supervisory control function, hence protecting the safety of people or articles.
Because the video cameras of the conventional remote supervisory control system need to be placed at fixed sites, the conventional remote supervisory control system can only provide image information in a fixed range. For a mobile person, because he can freely enter or leave the monitored range, the conventional remote supervisory control system cannot provide complete supervisory control, and dead spaces in safety may easily arise.
Besides, the conventional remote supervisory control system only provides remote supervisory control function, but cannot provide extra services like personal exclusive database management, personal life secretary, communication service of single telephone number, and so on, its service range is very narrow, and cannot provide all-purpose services for a user.